Method for spinal adjustment using hinged spinal insert device

ABSTRACT

A spinal insert provides for a method of spinal adjustment to adjust inter-vertebral spacing and alignment of vertebral bodies relative to a pre-determined reference line determined from measurement including but not limited to the pelvic incidence, pelvic tilt, and C7 plumb line. The device includes an upper arm and a lower arm extending outwardly from a base section defining a frame. An adjustment member is positioned between the upper arm and the lower arm. The adjustment member has a plurality of distinct lengths measured straight through a center of the adjustment member. The adjustment member is rotatable wherein an angle between the upper arm and the lower arm is selectively adjustable by rotation of the adjustment member. Spacing of vertebral endplates using a plurality of the frames described permits adjustment of the vertebral bodies to a desired angle relative to the pelvic orientation of an individual patient.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 13/838,045filed on Mar. 15, 2013 and issued on Jan. 19, 2016, and continuationapplication Ser. No. 14/453,077 filed on Aug. 6, 2014.

BACKGROUND OF THE DISCLOSURE Field of the Disclosure

The disclosure relates to spinal insert devices and more particularlypertains to a new spinal insert device for adjusting inter-vertebralspacing and alignment of the spine relative to pelvic incidence, pelvictilt and overall sagittal alignment.

SUMMARY OF THE DISCLOSURE

An embodiment of the disclosure meets the needs presented above bygenerally comprising an upper arm having a substantially planar uppersurface and a lower arm having a substantially planar lower surface. Abase section is coupled to and extends between the upper arm and thelower arm defining a frame. Each of the upper arm and the lower armextends outwardly from the base section. A hinge couples the upper armto the base section such that the upper arm is pivotable relative to thebase section. An adjustment member is positioned between the upper armand the lower arm. The adjustment member has a plurality of distinctlengths measured straight through a center of the adjustment member. Theadjustment member is rotatable wherein an angle between the upper armand the lower arm is selectively adjustable by rotation of theadjustment member.

There has thus been outlined, rather broadly, the more importantfeatures of the disclosure in order that the detailed descriptionthereof that follows may be better understood, and in order that thepresent contribution to the art may be better appreciated. There areadditional features of the disclosure that will be described hereinafterand which will form the subject matter of the claims appended hereto.

The objects of the disclosure, along with the various features ofnovelty which characterize the disclosure, are pointed out withparticularity in the claims annexed to and forming a part of thisdisclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure will be better understood and objects other than thoseset forth above will become apparent when consideration is given to thefollowing detailed description thereof. Such description makes referenceto the annexed drawings wherein:

FIG. 1 is a side view of a spinal insert according to an embodiment ofthe disclosure.

FIG. 2 is a front view of an embodiment of the disclosure.

FIG. 3 is a back view of an adjustment member according to an embodimentof the disclosure.

FIG. 4 is a back view of an adjustment member according to an embodimentof the disclosure.

FIG. 5 is a front view of an embodiment of the disclosure for use in aTLIF surgical approach.

FIG. 6 is a top view of an embodiment of the disclosure using a TLIFsurgical approach.

FIG. 7 is a back view of an embodiment of the disclosure for use in aPLIF surgical approach.

FIG. 8 is a top view of an embodiment of the disclosure using a PLIFsurgical approach.

FIG. 9 is a schematic view of a method according to an embodiment of thedisclosure.

FIG. 10 is a side view demonstrating measurement of pelvic incidence.

FIG. 11 is a side view demonstrating spinal alignment relative to a C7plumb line.

FIG. 12 is a graph of intervertebral spacing between adjacent vertebralendplates to achieve a desired cumulative spinal adjustment.

FIG. 13 is a side view of an embodiment of the disclosure.

FIG. 14 is a cross-sectional view of an embodiment of the disclosuretaken along line 14-14 of FIG. 13.

FIG. 15 is a top view of an embodiment of the disclosure.

DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference now to the drawings, and in particular to FIGS. 1 through15 thereof, a new spinal insert device embodying the principles andconcepts of an embodiment of the disclosure and generally designated bythe reference numeral 10 will be described.

As best illustrated in FIGS. 1 through 15, an embodiment of the spinalinsert device 10 generally comprises a frame 12 having a rigid upper arm14, a rigid lower arm 16 and a base section 18 extending betweenproximal ends 22,24 of the upper arm 14 and the lower arm 16. Each ofthe upper arm 14 and the lower arm 16 extend outwardly from the basesection 18. The upper arm 14 has a planar upper surface 20 and the lowerarm 16 has a planar lower surface 26 each configured for and constructedof material suitable for abutting and fixation to vertebral bodies 28 ofa spine 30. A hinge 170 couples the proximal end 22 of the upper arm 14to the base section 18 wherein the upper arm 14 remains substantiallyplanar but is pivotable relative to the base section 18.

An adjustment member 32 is positioned between the upper arm 14 and thelower arm 16. The adjustment member 32 may be disc-like and have anouter perimeter edge 34. The adjustment member 32 has a plurality ofdistinct lengths measured straight through a center 36 of the adjustmentmember 32 and straight across the adjustment member 32. Thus, theadjustment member 32 is rotatable wherein an angle between the upper arm14 and the lower arm 16, and consequently an angle between the uppersurface 20 and the lower surface 26, is selectively adjustable byrotation of the adjustment member 32.

A beam 100 extends between the upper arm 14 and the lower arm 16providing stiffness through the upper arm 14 and lower arm 16. A slit102 extends through the beam 100 between the upper arm 14 and the lowerarm 16 permitting movement of the upper arm 14 when the adjustmentmember 32 is rotated. The alternative embodiment 98 may include thestructure described above where the beam 100 does not prevent suchstructure from being incorporated into the alternative embodiment 98.The base section 18 may be formed by a back edge of the beam 100 or mayextend a full length across the upper arm 14 and lower arm 16.

A channel 104 may be provided extending through the beam 100. Theopening 62 is aligned with the channel 104. The adjustment shaft 64extends from the adjustment member 32 through the channel 104 and intothe opening 62 through the base section 18.

The slit 102 divides the beam 100 into an upper section 106 extendingfrom the upper arm 14 and a lower section 108 extending from the lowerarm 16. The slit 102 may define a tongue 110 and groove 112 positionedin and extending along a length of the beam 100 between the uppersection 106 of the beam 100 and the lower section 108 of the beam 100.The tongue 110 is positioned in the groove 112 providing structuralsupport laterally preventing twisting of the upper arm 14 relative tothe lower arm 16.

The adjustment member 32 may be is seated in an upper slot 114 in theupper extension 54 and a lower slot 116 in the lower extension 56. Theupper slot 114 may also be provided in the embodiment of the device 10as shown in FIGS. 1 through 6. The upper slot 114 and lower slot 116 mayalso be integrated directly into the upper arm 14 and the lower arm 16respectively.

The frame 12 may typically be inserted from posterior approach with atechnique known as a posterior lumbar interbody fusion (PLIF) or theframe 12, described below and exemplified in FIG. 5, may be used withinserting the frame 12 obliquely from the posterior approach with thetechnique known as a transforaminal lumbar interbody fusion (TLIF). Withboth, the goal is still to adjust front to back curvature of the spine30 (or sagittal plane). Thus, in the TLIF approach the frame 12 isinserted obliquely between the adjacent vertebral bodies 28 and theupper surface 20 and lower surface 26 are angled such that they remainin the proper front to back orientation to provide desired lordosis whenthe frame 12 is positioned between the adjacent vertebral bodies 28.This is similar to the embodiment in FIG. 5 wherein the upper surface 20of the upper arm 14 and the lower surface 26 of the lower arm 16 mayalso be angled relative to each other to further provide for lateralspacing of the discs 28 to adjust lateral curvature of the spine 30 aswell as front to back lordosis. The relative planes of the upper surface20 of the upper arm 14 and the lower surface 26 of the lower arm 16 aredetermined based on the desired end position after the adjustment member32 has been moved.

As can be seen generally in FIGS. 5, 7, 13, and 14, a plurality ofserrations 120 is positioned on and may be coextensive with the uppersurface 20 of the upper arm 14. An upper surface of the beam 100 may becoplanar with the upper surface 20 of the upper arm 14 and also haveserrations 120. Similarly, the lower surface 26 of the lower arm 16 alsohas serrations 120 to prevent slippage and provide secure engagement ofthe device 10 to each vertebral body 28. A bottom surface of the beam100 is similarly coplanar with the lower surface 26 and includesserrations 120. Edges 128 may be curved to extend smoothly away from theupper surface 20 and lower surface 26. The edges 128 are smooth withoutserration to facilitate insertion and positioning of the frame 12 withminimal trauma to the patient.

The outer perimeter edge 34 of the adjustment member 32 may have aplurality of opposed substantially parallel straight sections 38. Eachof the opposed straight sections 38 is a unique distance apart withrespect to each other opposed straight sections 38 on the adjustmentmember 32. Alternatively, the outer perimeter edge 34 of the adjustmentmember 32 may have a curved section 40 and a plurality of straight sides42. Each straight side 42 is positioned opposite the curved section 40.Each straight side 42 is a unique distance measured transversely fromthe straight side 42 to the curved section 40 with respect to each otherstraight side 42. The curved section 40 facilitates smooth rotation ofthe adjustment member 32 to minimize potential trauma to the surroundingtissues while the adjustment member 32 is rotated. A junction 44 betweeneach of the straight sections 38 may be curved wherein the junctions 44are configured for facilitating smooth rotation of the adjustment member32 between the upper arm 14 and the lower arm 16 while still permittingeach straight section 38 to rest against the upper arm 14 or lower arm16 to facilitate retaining the adjustment member 32 in the desired finalposition. Similarly, a junction 46 between each of the straight sides 42may be arcuate wherein the junctions 46 are configured for facilitatingsmooth rotation of the adjustment member 32 between the upper arm 14 andthe lower arm 16 while allowing the straight sides 42 to hold theadjustment member in the desired final position.

To enhance support the upper arm 14 and lower arm 16 the adjustmentmember 32 may be positioned proximate a distal end 48 of the upper arm14 and a distal end 50 of the lower arm 16 relative to the base section18 of the frame 12. An upper extension 54 is coupled to and extends fromthe distal end 48 of the upper arm 14 relative to the base section 18and a lower extension 56 is coupled to and extends from the distal end50 of the lower arm 16 relative to the base section 18. The upperextension 54 and the lower extension 56 extend towards each other whileextending away from the base section 18 of the frame 12 to facilitateinsertion into a patient and positioning between the vertebral bodies28. Outwardly facing surfaces 58,60 of the upper extension 54 and thelower extension 56 may be curved or otherwise shaped to facilitateinsertion and proper positioning with minimal trauma to surroundingtissues.

The adjustment member 32 may be provided in a variety of sizes such thatfor one adjustment member 32 an angle between the upper surface 20 ofthe upper arm 14 and the lower surface 26 of the lower arm 16 isselectively adjustable between zero degrees and six degrees in twodegree increments. For another adjustment member 32 an angle between theupper surface 20 of the upper arm 14 and the lower surface 26 of thelower arm 16 may be selectively adjustable between six degrees andtwelve degrees in two degree increments. Another adjustment member 32may be provided such that an angle between the upper surface 20 of theupper arm 14 and the lower surface 26 of the lower arm 16 is selectivelyadjustable between eight degrees and fourteen degrees in two degreeincrements. Yet another adjustment member 32 may be provided such thatan angle between the upper surface 20 of the upper arm 14 and the lowersurface 26 of the lower arm 16 is selectively adjustable between tendegrees and nineteen degrees in three degree increments. Still anotheradjustment member 32 may be provided such that an angle between theupper surface 20 of the upper arm 14 and the lower surface 26 of thelower arm 16 is selectively adjustable between ten degrees and sixteendegrees in two degree increments. Still yet another adjustment member 32may be provided such that an angle between the upper surface 20 of theupper arm 14 and the lower surface 26 of the lower arm 16 is selectivelyadjustable between twelve degrees and twenty one degrees in three degreeincrements. Other ranges and incremental changes may be provided asdesired.

In use, the device 10 provides dynamic movement of the upper arm 14 andlower arm 16 allowing for a method 70 of spinal adjustment to correctsagittal balance by dynamic movement or adjustment of the device 10while the device 10 is in place engaging adjacent vertebral bodies 28.The method 70 comprises a step 72 of having one or more frames 12 eachhaving an associated adjustment member 32 as described above. The method70 includes another step 74 of inserting each frame 12 between anassociated adjacent pair of vertebral endplates 92,94 wherein an uppersurface 66 of the frame 12, which may be the upper surface 20 of theupper arm 14, abuts an upper one of the vertebral endplates 92 and alower surface 78 of the frame 12, which may be the lower surface 26 ofthe lower arm 16, abuts a lower one of the vertebral endplates 94. Thismay be done after removing an intervertebral disc. Another step 88 isperformed by adjusting an angle between the upper surface 66 and thelower surface 76 of each frame 12 wherein an angle between theassociated pair of vertebral endplates 92,94 is adjusted. The method 70may include adjustment of only one pair of vertebral endplates 92,94 butmay also comprise adjusting a cumulative angle between each of multiplepairs of vertebral endplates 92,94 to adjust alignment of the spine 30formed by a plurality of vertebral bodies 28 relative to pre-determinedreference lines determined from measurements of pelvic incidence.Additional factors may include pelvic tilt and C7 plumb line. Desiredangles between each pair of vertebral endplates 92,94 may be determinedaccording to the chart of FIG. 12. Additional factors for eachparticular patient may also be taken into account in addition to pelvicincidence, pelvic tilt and C7 plumb line when determining exact lordosiscorrections between specific adjacent vertebral bodies 28.

As shown in FIG. 12, total lumbar lordosis (LL) required is wellestimated by the formula LL=pelvic incidence (PI) plus ten (10) degrees,or using a more rigid formula wherein LL=0.56×PI+33. Current practice isfor two-thirds of the cumulative lordosis correction to be provided inbetween the L4/5 and L5/S1 vertebral bodies and the remaining correctiondivided evenly between L1/2, L2/3, and L3/4 vertebral bodies. Theseformulas provide a framework for determining the patient's sagittalimbalance that may need correction. Other factors may be included indetermining total corrective lordosis if there is a positive sagittalimbalance on standing 36-inch radiographs as determined by the C7 plumbline. For example, a patient with hyper thoracic kyphosis may requireadditional lumbar lordosis to provide desired results.

As demonstrated in FIG. 12, pelvic incidence is measured by drawing aline 130 from the midpoint 132 of the S1 superior endplate 134 to thecenter of the midpoint 136 between both femoral heads. A second line 138is drawn parallel to a perpendicular line from the S1 endplate 134 withthe starting point at the midpoint 132 of the S1 superior endplate 134.The angle 140 measured between these two lines 130,138 is the pelvicincidence. This measurement defines the relationship between the spineand the pelvis and can be used to predict the amount of lumbar lordosisneeded to maintain a neutral sagittal balance. As also shown in FIG. 14,pelvic tilt is measured using the line 130 from the midpoint 136 betweenthe center of the femoral heads to the midpoint 132 of the S1 superiorendplate 134. A vertical reference line 142 is drawn vertically from themidpoint 136 between both femoral heads. An angle 144 created betweenthe line 130 and the vertical reference line 142 represents the pelvictilt. The angle 144 helps the surgeon determine if the patient iscompensating for lack of lumbar lordosis by increasing their pelvic tiltto maintain a neutral sagittal balance. As shown in FIG. 13, C7 plumbline 146 is drawn on a 36 inch lateral radiograph by finding the middleof the C7 vertebral body 148 and drawing a vertical line downward. Ameasurement from the posterior superior corner 150 of the S1 vertebralendplate 134 to the C7 plumb line 146 is measured. This determines thepatient's sagittal balance. A positioning of the C7 plumb line 146posterior to the superior corner 154 of the S1 endplate is considered anegative sagittal balance, and a positive value is noted when the C7plumb line 146 is anterior to the posterior superior corner 150 of theS1 vertebral endplate 134. A positive sagittal balance value of greaterthan 5 centimeters is considered abnormal.

With the above information for a particular patient, incrementaladjustment between adjacent vertebral endplates 92,94 may be determinedconsistent with FIG. 8 and any additional factors deemed necessary toprovide the desired total cumulative adjustment of the spine 30 relativeto the position of the pelvis 82 to reestablish sagittal balance asopposed to merely straightening the spine 30 alone. After the adjustmentmember 32 is rotated to provide a desired angle between adjacentvertebral bodies 28, another step 90 may be performed wherein pediclescrews are placed to stabilize the spine and maintain the desiredposition. Pressure on the frame 12 may hold the frame 12 in place whilethe pedicle screws are placed. The permanent alignment is held by thepedicle screws and rod construct or by other posterior fixation methods.

With respect to the above description then, it is to be realized thatthe optimum dimensional relationships for the parts of an embodimentenabled by the disclosure, to include variations in size, materials,shape, form, function and manner of operation, assembly and use, aredeemed readily apparent and obvious to one skilled in the art, and allequivalent relationships to those illustrated in the drawings anddescribed in the specification are intended to be encompassed by anembodiment of the disclosure.

Therefore, the foregoing is considered as illustrative only of theprinciples of the disclosure. Further, since numerous modifications andchanges will readily occur to those skilled in the art, it is notdesired to limit the disclosure to the exact construction and operationshown and described, and accordingly, all suitable modifications andequivalents may be resorted to, falling within the scope of thedisclosure. In this patent document, the word “comprising” is used inits non-limiting sense to mean that items following the word areincluded, but items not specifically mentioned are not excluded. Areference to an element by the indefinite article “a” does not excludethe possibility that more than one of the element is present, unless thecontext clearly requires that there be only one of the elements.

I claim:
 1. A method of spinal adjustment to correct spinal curvature,the steps of the method comprising: having a plurality of frames, eachframe having an upper arm, a lower arm and a base section, each of saidupper arm and said lower arm extending outwardly from said base section,said upper arm having a planar upper surface, said lower arm having aplanar lower surface; having a plurality of adjustment members, eachadjustment member being positioned between said upper arm and said lowerarm of an associated one of said frames, said adjustment member havingan outer perimeter, said adjustment member having a plurality ofdistinct lengths measured straight through a center of said adjustmentmember, said adjustment member being rotatable wherein an angle betweensaid upper arm and said lower arm of said associated frame isselectively adjustable by rotation of said adjustment member; insertingeach frame between an associated adjacent pair of adjacent vertebralendplates after removing an intervertebral disc wherein an upper surfaceof said frame abuts an upper one of said adjacent vertebral endplatesand a lower surface of said frame abuts a lower one of said adjacentvertebral endplates; and adjusting an angle between said upper surfaceand said lower surface of each said frame wherein an angle between saidassociated pair of vertebral endplates is adjusted; and adjusting acumulative angle between each said pair of adjacent vertebral endplatesto adjust alignment of a plurality of vertebral bodies relative to apre-determined reference line determined using measurements of pelvicincidence, pelvic tilt, and C7 plumb line.